Welcome to Subeta! There are lots of ways to change your pet appearances, elixirs, potions, or some pets have special ways to be obtained such as zappers, etc.

You can check out SubetaLodge's list of pets (linked below) to see which colours you like, and start from there? :)

Useful Links:

What to do on Subeta? Useful general information for newbies Finding friends (Chit Chat) SubetaLodge (Offsite item database, pet colours etc.)
FAQ